1. Field of the Invention
The invention in question is concerned with compositions containing aluminium alkyl aceto acetate compounds, their manufacture and use as additives to printing inks.
2. Description of the Prior Art
The use of aluminium tris-acetyl acetonate and aluminium tris-ethyl aceto acetate as a component in acrylate adhesives, silicone resins, intaglio inks and similar is known. For example, U.S. Pat. No. 4,221,593 discloses the use of aluminium di-isopropoxide monoethyl aceto acetate and aluminium tris-ethyl aceto acetate as gelling agents for paint binders. Depending on the reaction conditions aluminium tris-acetyl acetonate and aluminium tris-ethyl aceto acetate act as cross-linking agent of the material in question. Systems treated in this way have advantages in application. They have improved rheology, higher resistance against environmental and temperature influences or increased strength (hardness, adhesion properties). Aluminium tris-acetyl acetonate has disadvantages with regard to the toxicity, high costs of raw materials, complicated synthesis, the solid aggregate state and the low solubility in all customary solvents. Aluminium tris-ethyl aceto acetate also has low solubility in all customary solvents and a high tendency to precipitation of solid matter as a result of crystallisation phenomena.
U.S. Pat. No. 4,264,370 and GB-A-772 144 disclose mixtures containing glycol compounds, e.g., polyalkyl glycols, and aluminium compounds, with the aluminium compounds being manufactured by conversion of aluminium alcoholates with substochiometric amounts of -keto-carboxylates. The aluminium compounds according to U.S. Pat. No. 4,264,370 and GB-A-771 144 always contain at least one alkoxylate group.
The task of the invention in question is to develop aluminium compounds which do not have any or at least most of the disadvantages described above. In particular, the compounds have to be suitable as additives for printing inks and correspondingly to have a high compatibility with printing ink binders, in particular for offset printing.